Structure for extendable bicycles

ABSTRACT

An improved structure for expandable bicycles to facilitate storing of a bicycle includes a cross bar which has one end fastened to the front fork of the bicycle and a sliding member slidable horizontally on the cross bar to alter the relative position of the front fork and the rear fork. The sliding member has a fastening member to fasten the head and seat of the bicycle on selected locations. Thus the bicycle may be extended as desired and stored conveniently.

FIELD OF THE INVENTION

The present invention relates to an improved structure for extendablebicycles and particularly to a structure that has a sliding member tomove a cross bar of a bicycle to alter the relative distance of thefront fork and the rear fork to achieve extension desired.

BACKGROUND OF THE INVENTION

In the earlier days bicycles are transport vehicles many people use inwork or daily life. These days the bicycle is well developed, and itstechniques are quite matured. Besides serving as a transport vehicle, italso is widely used as a recreational instrument, exercise tool, orleisure activity facility rather than a necessary tool of daily life. Incountries where population density is high, storage function of thebicycle becomes an important feature to fit the changes of time andpeople's living environment.

To tackle the bicycle storage problem, the conventional approach adoptsfolding. While the folding bicycle can reduce the size significantly,the folding procedures are quite complicated. They are not easy forchildren to do. And the folding joints could injure people if notproperly handled. Moreover, the folding joints tended to become loose ordamaged after bent for a long period of time.

There are other types of extendable bicycles (referring to FIGS. 1 and2). One example is to adopt a round cross bar movable in a main frame toachieve extension function. But the single round cross bar tends to turnduring sliding. To remedy this problem, another example is to adopt asingle but non-circular cross bar slidable in the main frame. While sucha design can prevent the cross bar from turning, it is fastened througha pin hole and a pin. Its operation is troublesome. If the pin werelost, the storage function of the bicycle also cannot be done.

SUMMARY OF THE INVENTION

Therefore the primary object of the present invention is to provide anextendable bicycle to facilitate storing. It includes:

-   -   at least one cross bar which is a portion of the main frame of        the bicycle to support and couple all the rest elements of the        bicycle. The cross bar is coupled with a first fastening dock        and a second fastening dock on the front end and the rear end.        The first fastening dock on the front end has a first bore to        install the front fork of the bicycle;    -   a sliding member which has a second bore formed on the side wall        and a third bore on the top side. The second bore allows the        cross bar to run through and sliding therein. The third bore        aims to install the rear fork; and    -   a fastening member which includes a fastening plate and a        fastening rod. The sliding member has a first fastening hole to        couple the fastening member and the sliding member. The        fastening plate has a second fastening hole to install the        fastening rod.

Another object of the invention is to improve the complicated storingprocedures of the conventional folding bicycles, and the risk ofinjuring people caused by the folding joints and the concern of easilydamage occurred to the folding joints.

Yet another object of the invention is to improve the operation of theextension mechanism of the extendable bicycle.

The foregoing, as well as additional objects, features and advantages ofthe invention will be more readily apparent from the following detaileddescription, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a conventional extendable bicycle.

FIG. 2 is a schematic view of another conventional extendable bicycle.

FIG. 3 is an exploded view of the present invention.

FIG. 4 is a perspective view of the invention.

FIG. 5 is a schematic view of an embodiment of the present invention.

FIG. 6A is a schematic view of an embodiment of the present invention inan operating condition.

FIG. 6B is a schematic view of an embodiment of the present invention inanother operating condition.

FIG. 7 is a schematic view of a second embodiment of the presentinvention.

FIG. 8 is a schematic view of a third embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please referring to FIGS. 3, 4 and 5, the present invention includes anextension mechanism 1 which has at least one cross bar 10 to become aportion of the main frame of a bicycle to support and couple all therest elements of the bicycle. The cross bar 10 is coupled with a firstfastening dock 11 on the front end and a second fastening dock 11′ onthe rear end. The first fastening dock 11 has a first bore 110 toinstall a front fork 12 of the bicycle. A sliding member 13 is providedthat has a second bore 130 formed on the side walls thereof to allow thecross bar 10 to run through. The second bore 130 has two openings on twoends each is coupled with a ball bearing 25 to facilitate sliding of thecross bar 15. The sliding member 13 further has a third bore 131 on thetop side to install a rear fork 14.

There is a fastening member 15 which includes a fastening plate 150 anda fastening rod 151. The sliding member 13 has a first fastening hole132 to couple the fastening member 15 and the sliding member 13. Thefastening plate 150 is wedged in a trough 23 formed on the slidingmember 13 in a corresponding shape. The fastening plate 150 has a secondfastening hole 152 to couple the fastening rod 151 with the fasteningplate 150. The fastening plate 150 has a recess 24 matching the shape ofthe cross bar 10 run through the sliding member 13.

The fastening docks 11 and 11′ have respectively a fourth bore 16 and afifth bore 17 formed on one side wall to couple with the cross car 10.The locations of the fourth and fifth bores 16 and 17 correspond to thenumber and shape of the cross bar 10. The junctures of the fasteningdocks 11 and 11′ and the cross bar 10 have respectively an elasticelement 19 to reduce impact and damage caused by sliding. The fasteningdocks 11 and 11′ further have respectively a third fastening hole 22 toreceive a fastening element 18 to fasten the cross bar 10 in thefastening docks.

Referring to FIGS. 5, 6A and 6B, to extend or retract the bicyclethrough the extension mechanism 1, first, unfasten the fastening rod 151at a first position, the fastening plate 150 moves downwards withoutforming a tightly coupling with the cross bar 10 and the sliding member13; and the cross bar 10 may be moved and slid on the sliding member 13to shrink the distance between the front fork 12 and the rear fork 14 ata second position; then depress the fastening rod 151. As the fasteningrod 151 includes a cam handle, through the cam mechanism, the fasteningplate 150 can be moved to clamp the cross bar tightly again to fix theposition.

Refer to FIGS. 7 and 8 for other embodiments of the invention. Thesliding member 13 is coupled on sliding tracks 20. Four bearings areprovided on the coaxial locations of two sides of the top section of thesliding member 13 (referring to a second embodiment), or on the coaxiallocations of two side walls of the sliding member 13 (referring to athird embodiment). The sliding tracks 20 are located on the upper sideand the lower side of the sliding member 13, or on the left side and theright side of the sliding member 13. By means of the process previouslydiscussed, the relative distance between the front fork 12 and the rearfork 14 may be altered.

While the preferred embodiments of the invention have been set forth forthe purpose of disclosure, modifications of the disclosed embodiments ofthe invention as well as other embodiments thereof may occur to thoseskilled in the art. Accordingly, the appended claims are intended tocover all embodiments which do not depart from the spirit and scope ofthe invention.

1. An improved structure for expandable bicycles for use on a main frameof a bicycle to extend or retract the bicycle by altering the relativeposition of a bicycle head, comprising: at least one cross bar which isa portion of the main frame for supporting and coupling all otherelements of the bicycle having a first fastening dock on a front sideand a second fastening dock on a rear side, the first fastening dockhaving a first bore for installing a front fork; a sliding member havinga second bore on side walls thereof to allow the cross bar to runthrough and slide therein, a third bore on a top side to install a rearfork, and a first fastening hole; and a fastening member including afastening plate and a fastening rod, the fastening plate being coupledwith the sliding member through the first fastening hole, the fasteningplate having a second fastening hole corresponding to the firstfastening hole to install the fastening rod.
 2. The improved structurefor expandable bicycles of claim 1 further having an elastic elementlocated on the juncture of the cross bar and each fastening dock toabsorb impact when the sliding member slides on the cross bar.
 3. Theimproved structure for expandable bicycles of claim 2, wherein theelastic element is a soft pad or a spring.
 4. The improved structure forexpandable bicycles of claim 1, wherein the first fastening dock and thesecond fastening dock have respectively a fourth bore and a fifth boreon a side wall thereof to couple with the cross bar for fastening. 5.The improved structure for expandable bicycles of claim 1, wherein thecross bar is fastened to the fastening dock through a fastening element.6. The improved structure for expandable bicycles of claim 5, whereinthe fastening element is a screw or an anchor nail.
 7. The improvedstructure for expandable bicycles of claim 5, wherein the fasteningdocks have a third fastening hole.
 8. The improved structure forexpandable bicycles of claim 1, wherein the sliding member has a troughmating the fastening plate to couple with the fastening plate.
 9. Theimproved structure for expandable bicycles of claim 1, wherein thefastening plate has a recess mating the cross bar run through thesliding member.
 10. The improved structure for expandable bicycles ofclaim 1, wherein the fastening rod has a coupling section on the bottomthereof to fasten the fastening plate, the cross bar and the slidingmember and close gaps formed therebetween to anchor the sliding memberon a desired location.
 11. The improved structure for expandablebicycles of claim 10, wherein the coupling section is a bolt or a latchtenon.
 12. The improved structure for expandable bicycles of claim 1,wherein the fastening rod has a cam on the top end thereof which iseccentric to fasten the fastening plate, the cross bar and the slidingmember tightly.
 13. The improved structure for expandable bicycles ofclaim 1, wherein the second bore has two openings on two sides to holdrespectively a ball bearing or a roller to facilitate sliding of thecross bar.